1. Field of the invention
The present invention relates to an alignment apparatus for use in a process for manufacturing a liquid crystal display (LCD) device, and more particularly, for the substrate.
2. Description of Related Art
In general, a process for manufacturing a LCD device includes many steps (such as a cleaning process, a layer-depositing process and a developing process) to fabricate various elements on a substrate. After completion of the above-mentioned processes, a drying process is then performed. In preparation for drying, a robot arm moves the substrate from process to process until it is positioned into an alignment apparatus.
A conventional alignment apparatus employed in a drying process will be explained hereinafter as one example ,with reference to the accompanying drawings.
FIG. 1 is a plan view of a conventional alignment apparatus. A substrate 5 is positioned over a table 2 of the alignment apparatus. A plurality of guide pins 1 (eight pins in all) are located on the peripheral portion of the table 2 with a pair of guide pins 1 near each corner of the substrate 5.
FIGS. 2A and 2B are cross-sectional views taken along linexe2x80x94of FIG. 1. As shown in FIG. 2A, the substrate 5 is positioned on the lift pins 3 by a robot arm (not shown). Initially, the lift pins 3 extend above the table 2 for receiving the substrate 5. When the lift pins 3 descend with the supported substrate 5 to the table 2 of the alignment apparatus, as shown in FIG. 2B, the substrate 5 is aligned in a determined area defined by the guide pins 1. Proximity pins 4 hold the substrate 5 above the table 2 as the lift pins 3 continue to descend out of contact with the substrate 5. The proximity pins 4 have a portion that extends about 0.2 from the surface of the table 2. When the substrate 5 is in contact with and positioned on the proximity pins 4 after a descent of the lift pins 3, a hot-plate (not shown) having a high temperature dries the substrate 5.
However, as shown in FIG. 3, the substrate 5 can be misaligned as it descends towards the table 2 if it is not properly disposed within the predetermined space as defined by the guide pins 1.
The reason of the misalignment between the substrate 5 and the table 2 is not only that the dynamic error occurs when the robot arm carries the substrate 5 on the lift pins 3 but also that the lift pins 3 descend the substrate 5 without compensating for the dynamic error. If misaligned, the substrate 5 can be damaged or become stained as it contacts the guide pins 1.
In order to overcome the problems described above, a preferred embodiment of the present invention provides an alignment apparatus for use in a process of manufacturing an LCD device, which has plural alignment pins.
Another object of the present invention provides an alignment apparatus that prevents misalignment between a substrate and a table so as to avoid damage to the substrate.
In order to achieve the above objects, the preferred embodiment of the present invention provides an alignment apparatus, including: a table; guides positioned on a periphiral portion of the table; an acceptance device surrounded by the guide; a lift mechanism positioned on the table and moving between under the acceptance device and over the end portion of the guide; a transport for carrying a substrate on the lift when the lift projects over the end portion of the guide; a shifter for the lift into the acceptance device and for setting the substrate into the acceptance device; and a position-compensating mechanism for preventing the substrate from being positioned on the guide.
The position-compensating mechanism reciprocatingly moves a determined distance that is transverse and parallel to the table plane. The position-compensating mechanism further projects through and is perpendicular to the table. The position-compensating mechanism also moves from the peripheral portion to the edge of the acceptance device to align the substrate when the lift is positioned over the end portion of the guide.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.